1. The presence or absence of oxygen in the materials may result in the A burning of the materials B. melting of the materials C. change in the materials D. materials remain the same 2. Iron, nails, cans and other metals with iron when exposed to moisture may develop A. dust B. rust C. heat D. fuel 3. The inner part of the potatoes and apples change in color because of A. fuel in it B. chemicals in it C. exposure to heat D. exposure to oxygen 4. The process of burning materials with the aid of o
Answer (1)
1. A. burning of the materialsOxygen is needed for combustion. Without oxygen, burning won’t happen. This is why fire needs air (which contains oxygen) to keep burning.2. B. rustWhen iron comes in contact with water (moisture) and oxygen, a chemical reaction occurs, forming rust (kalawang). It weakens the metal over time.3. D. exposure to oxygenWhen the inside of fruits like apples and potatoes is exposed to air, they react with oxygen, causing oxidation. This is what makes them turn brown.4. CombustionCombustion is the scientific term for burning. It needs a fuel and oxygen to produce heat and light.
